The use of Internet as a general means for communication is continuously growing. The success of the Internet depends on a fruitful cooperation between manufacturers and network providers in the development of standards. The protocol suite TCP/IP has become a basic standard for Internet communication. Other standards, such as the Real Time Protocol (RTP) adds functionality to the network and allows for real time services e.g. to transfer audio and video information. To maintain quality of real time services the network must provide satisfactory characteristics throughout a real time session. Therefore, standards have been developed to communicate and process requirements e.g. concerning bit rate, and delay characteristics. In general Quality of Service (QoS) has become an important topic in the further development of Internet. To initiate a communications session between parties a handshaking procedure will first have to take place. The Session Initiation Protocol, SIP, has been developed for handling of Internet based communication. An originating party making a call towards another party (a person, information service or transaction service) initiates this procedure. The call has to be communicated to the called party who can either accept or reject the call. If a call is accepted further conditions have to be fulfilled to cater for compatibility between the means for communication that are available for the involved parties. Traditional methods for communication do not take full advantage of an environment where each party may use a choice of terminals connected by different access networks operated by different access network operators.
In general, a user who makes a network access will use a particular terminal throughout the user session and is, thus, limited to the media types supported by that particular terminal. For example, the terminal may be a mobile telephone. Many terminals, e.g. a mobile telephone, can support several media types such as voice and data. Several simultaneously ongoing sessions may be initiated at one and the same terminal, e.g. a mobile telephone, thereby enabling multimedia communication. However, a mobile phone is primarily optimized for portability and intended for voice communication and other media may be adversely affected by technical limitations such as limited processing power, memory limitations, and a small display screen. Similarly, other types of terminals are often optimized for a particular application. Thus, e.g., a Personal Digital Assistant, PDA, has a reasonably sized display screen and allows connection to a data network. A PDA is, therefore, convenient for conveying printed information such as text and image. However, a PDA may not have means for voice communication. A Personal Computer, PC, generally has enough capacity to allow for simultaneous voice and data communication over a network. However, a PC is generally less mobile than, e.g., a mobile phone and a lap-top PC usually has a battery capacity that severely limits the operative time. Thus, depending on the circumstances, a user may prefer a type of terminal that is best adapted to the prevailing communication conditions and type of desired communication.
Although standards are developed that allow communication between terminals of various manufactures there is still a problem of compatibility. For example, a user having a PC and who communicates with another user having a mobile telephone may experience compatibility problems related to the very different terminal characteristics in this case. Although both terminals can communicate from a technical point of view, from the user perspective there is e.g. an incompatibility problem related to the fact that a mobile phone can present only a very limited amount of information on a small display screen.
Besides an environment of end user systems that restricts type and quality of communication, a user might experience other limiting factors such as the availability to a called party for communication. In general, the term end user context shall, in this document, denominate a set of factors that affect the communication between parties. In particular, an end user context includes data on available end user systems and data pertaining to user communication preferences such as time and availability for communication.
It can be foreseen that end users at each instance have simultaneous access to a plurality of end user systems each having specific characteristics. It would, therefore, be advantageous to simultaneously use several end user systems according to user preferences in order to make optimal use of the various media types supported by these systems. It would, further, be advantageous to make said combination in dependence of user contexts associated with the communicating parties. User contexts may vary with time and place.
There is, thus, a need for a method and arrangement to establish a user-to-user session involving, for each end user, at least one of a plurality of simultaneously accessible end user systems, said session further being dependent of user current contexts associated with the communicating parties.